This invention relates to wireless communication for mobile communications and computing appliances, and specifically to devices which incorporate both cellular communications capability, for wide area, mobile connectivity, and industrial, scientific and medical (ISM) band RF communications connectivity, for short range, mostly indoor connectivity, such as a cellular-personal digital assistant (PDA), or cell phone.
The industrial, scientific and medical (ISM) RF band, at 2.4 GHz, permits non-licensed operation of wireless communication devices, subject to certain constraints in terms of transmit power, modulation and bandwidth. Although the ISM band is broadly available worldwide, there are regional variations in the spectrum available, due to the existence of legacy RF systems in this band in certain countries. Specifically, France uses significantly less of the ISM band than do the rest of Europe and the United States of America. Although Japan now uses the same ISM frequency band as the United States of America and Europe, certain portions of that country still use a different spectrum of the ISM band, beginning and ending higher in the 2.4 GHz spectrum. The allowed bands for non-licensed operation are as follows:
A number of new and existing communications systems are designed to operate in these non-licensed bands. Some examples are:
802.11 This is a wireless IEEE standard and protocol for use with LAN systems, designed as a wireless replacement for office LAN communications. It comes in both Direct Sequence (DS) and Frequency Hopping (FH) variants both operating in the 2.4 GHz ISM bands. Variation of this standard are identified as 802.11a and 802.11b. 802.11b is an unlicensed national information infrastructure (UNII) protocol and operates in the 5 GHz band.
HomeRF This is a new wireless ISM band protocol for Shared Wireless Access Protocolxe2x80x94SWAP-CA Cordless Access, which specification is just undergoing completion. It is intended to provide cordless communications for voice and data for home networking applications, particularly for multimedia applications.
Bluetooth(trademark) Bluetooth(trademark) is a new short-range communications standard, designed for operation in the 2.4 GHz ISM band. Bluetooth(trademark) is intended primarily as a replacement for cables, providing connectivity over a short range between, for example, a PDA and Laptop or a Laptop and Cellular Phone. Bluetooth(trademark) is an RF alternative for IrDA connectivity. Bluetooth(trademark) is a trademark/service mark of Telefonaktiebolaget LM Ericsson, of Stockholm, Sweden for telecommunication equipment, computer communication equipment, including radio modems; and telecommunication and computer communication services.
Each of these protocols is constrained to operate within the allowed regulations of the non-licensed ISM band, which regulations vary according to the country of operation. The specifications of these systems define the frequencies of operation and allowable carrier frequencies and further define how the protocols differ between France, Japan, the USA and the rest of Europe.
In order to support the movement of portable equipment between different countries, which have differing ISM band allocations, it is necessary for an ISM band communications module in a device to be configured to the appropriate country in which the device is being operated. This is necessary to comply with national regulatory schemes and to avoid interference with other devices operating in the same portion of the ISM spectrum in a particular country or geographical region. For example, in moving a Bluetooth(trademark)-enabled device from the USA to France, the country_code within the Bluetooth(trademark) module must be reconfigured from the USA RF spectrum to the French RF spectrum, to avoid interference from devices operating in the USA ISM spectrum and outside of the French ISM spectrum. Reconfiguration is also required to avoid violating French regulations for non-licensed RF devices.
In most cases, such reconfiguration requires the user to manually alter the device configuration for a specific country using some kind of driver software. Some devices may be hard-configured to comply with the non-licensed frequency spectrum in only a single country, or geographical region, and are not capable of being re-configured. It is desirable, however, for an ISM band communications device to automatically configure itself to the RF spectrum of the country in which it is located, without user intervention.
ISM systems have historically not needed to roam between different regulatory regions, as they have traditionally been part of a fixed wireless system, such as a LAN. They are configured to function with the local RF spectrum, generally upon initial activation, by manual user intervention, e.g., configuration of device driver options.
Licensed, wide area cellular systems have provided automatic regional configuration to local spectrum variations by supporting multi-band terminals and/or subscriber identification module (SIM) roaming. This requires redundant hardware, such as a new terminal for SIM roaming, or additional RF hardware for multi-band terminals. SIM roaming requires manual intervention i.e., insertion of the SIM into a new terminal, in order to function. Multi-band devices adapt to the local band by scanning possible frequencies to detect the frequency of transmission of the local cell-sites. Prior art in non-licensed technology is either permanently configured to one country""s regulation or requires manual reconfiguration to change to a new country.
U.S. Pat. No. 5,729,680, to Belanger et al., granted Mar. 17, 1998, for Ad hoc initialization for wireless local area network, describes a method for bootstrapping unlicensed band communications devices from cold start, so that they are able to communicate, but does not teach or suggest a system or method for adapting to different geographic spectral differences.
U.S. Pat. No. 5,838,730, to Cripps, granted Nov. 17, 1998, for Radio transmitted/receiver for wireless local area network, describes a system which complies to the non-licensed band regulations of the United States of America.
U.S. Pat. No. 5,867,766, to Dinc et al., granted Feb. 2, 1999, for Technique for performing an automatic channel search and switch during talk-time in mobile transceivers, describes a system incorporating a single RF module, which configures its transmission frequencies by measuring the locally used transmission frequencies.
U.S. Pat. No. 5,881,372, to Kruys, granted Mar. 9, 1999, for Radio Communication Device and Method, describes a system which forces the radio module to only use the set of frequencies which are common globally and denies operation in any frequency which is not available in every country. This restricts the performance because only a small subset of channel frequencies are available globally in the ISM band.
The prior art in the ISM device field does not provide such an automatic configuration capability, in which information from a regulated/licensed wide area wireless technology, such as GSM, is used to configure a short-range, non-regulated wireless module in order to meet local frequency band variations in the non-licensed band.
A method of configuring an RF transceiver to receive a geographic-region specific message within a RF signal from a communications network, includes detecting the geographic-region specific message in a first RF transceiver operating in a first RF frequency spectrum; associating the detected geographic-region specific RF signal with a geographic region; generating a configuration command signal for the geographic region; and configuring a second RF transceiver to receive and transmits RF signals in a second RF frequency spectrum particular to the geographic region from the configuration command signal. A system for configuring an RF transceiver for use with a communications network, wherein the network includes transmitters which transmit a geographic-region specific message unique to the geographic region in which the transmitter is located, includes a mobile appliance having plural RF transceivers therein, including a first RF transceiver operating in a first RF frequency spectrum and a second RF transceiver operating in a second RF frequency spectrum, wherein the first RF transceiver receives the geographic-region specific message from a transmitter; a configuration mechanism for receiving the geographic-region specific message from the first transceiver, generating a configuration command signal, and transmitting the configuration. command signal to the second RF transceiver; wherein the second RF transceiver, upon receipt of the configuration command signal, changes an associated RF configuration to operate in the second RF frequency spectrum associated with the geographic region.
It is an object of the invention to provide automatic configuration of an non-licensed band RF module to local variations in allocation of the non-licensed RF spectrum, without user intervention.
Another object of the invention is to provide an ISM device which uses the country code broadcast information in a geographic region to reconfigure device RF capability to accommodate region specific messages.
These and other objects and advantages of the invention will become more fully apparent as the description which follows is read in conjunction with the drawings.